1. Field of the Invention:
The present invention relates to a seersucker weaving method and a seersucker loom. A seersucker is a plainwoven fabric having ground warp yarns and undulatory puckering warp yarns. Therefore the length of the puckering warp yarns woven in the seersucker is greater than that of the ground warp yarns woven in the same seersucker. A seersucker of a higher grade has greater undulations than that of a lower grade of seersucker.
2. Description of the Prior Art:
In a known seersucker weaving method such as disclosed in Japanese Laid-Open Patent Publication No. 53-65456, the length of the puckering warp yarns let off for every let-off cycle is greater than that of the ground warp yarns let off in the same let-off cycle, and the tension of the puckereing warp yarns is varied periodically at a period corresponding to several turns of the main shaft of the seersucker loom. When the puckering warp yarns are let off and the tension of the puckering warp yarns is controlled in such a manner, the puckering warp yarns slacken excessively during a low-tension period in which the tension of the puckering warp yarns is reduced if the length of the puckering warp yarns let off is much larger than that of the ground warp yarns and, consequently, the loom is unable to carry out a normal weaving operation because of the fact that the puckering warp yarns are woven in the fabric in loops, and then the droppers of the warp stop motion device engaging the puckering warp yarns drop to stop the loom or alternatively, a faulty shedding and the resultant faulty picking occurs. If the tension of the puckering warp yarns during a high-tension period in which the tension of the puckering warp yarns is increased is very high, it is impossible to weave a satisfactory seersucker because the length of the puckering warp yarns let off is absorbed by the elastic contraction of the puckering warp yarns and hence the puckering warp yarns are unable to be undulated to in a sufficiently high degree.
Thus, the known seersucker weaving method has problems in weaving a seersucker both when the length of the puckering warp yarns let off for every let-off cycle is comparatively large and when the tension of the puckering warp yarns is comparatively high. Accordingly, in any case, it is impossible to weave a seersucker on a high-speed loom, such as a water jet loom or an air jet loom, by this known seersucker weaving method.